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Home Electronics: Tube Coup

Ken Kessler

JULY 01, 2003

Tube amplifiers were supposed to be passé by now. Following World War II, transistor, or solid-state, amplification was to be the order of the day. Transistors were expected to replace vacuum tubes because they take up less space, operate more efficiently, run much cooler, and cost less—a classic example of electronics evolution. The only problem was that for pure pleasure in listening to music, transistors clearly represented a step in the wrong direction.

The two technologies achieve the same goal: Both amplify electronic signals that the loudspeaker converts to sound. By definition, all amplification, including that produced by tubes and transistors, is a distortion of the original musical signal. But because tubes and transistors operate differently, the distortions they produce differ. Audiophiles complain that transistors, which are made from solid silicon-based materials called semiconductors, distort the music in a harsh, dissonant manner. Conversely, the distortion from tubes, which are made of glass, metal, and filament, is said to sound warm and pleasing, and it reproduces vocals more realistically.

Another reason for the preference for tubes has to do with the way they behave when they are overdriven, or pushed to their amplification limits. When a tube amplifier is overworked, it compresses the sound and makes the music seem confined spatially. Overdrive a solid-state amplifier, and it produces a grating, unpleasant sound called clipping.

Limitations aside, there are visual differences to consider, as well. “Because tubes are transparent, with functioning innards, glowing and alive, I felt that they spoke to me,” explains Tim de Paravicini, a tube amplifier designer and founder of E.A.R./Yoshino, a company that manufactures both tube and transistor amplifiers. “Unlike transistors, which are solid inert lumps, tubes let you see the life of the music. They light up so you have a feeling of the inner workings.”

As is the case with most high-end products (such as electrostatic loudspeakers requiring a power source and sensitive turntables that sound miserable without a rock-solid foundation), you must overlook certain peculiarities of tube amps. In addition to being larger and running hotter, and therefore requiring more space and ventilation, tube amps also need tune-ups; some amplifiers do this automatically, but others require manual tweaking. And like lightbulbs, the tubes need to be changed every few years, which, if you are replacing a set of 16 large power tubes, could cost several thousand dollars. Nevertheless, more companies are producing high-end tubed electronics today than in the 1950s, when transistors had yet to emerge as a viable alternative.

Among the hundreds of brands producing tube amplifiers, a few models stand out, such as AudioValve’s Baldur 200 ($19,950), Conrad-Johnson’s MV60SE ($2,995), McIntosh’s C2200 ($4,500), and VTL’s 24-tube Wotan MB-1250 monoblock ($30,000 per pair). Manley Labs, another tube amp manufacturer, offers a monoblock called the Mahi—resulting in Mahi-Mahi for a two-channel setup ($2,500 per pair). The doyen of tube amp builders, however, is Audio Research, which makes preamps and power amps that maintain a proudly no-nonsense, utilitarian design—nothing superfluous.

“In the end,” asks Terry Dorn, Audio Research’s vice president of marketing, “is the difference [between tubes and transistors] worth the periodic maintenance required by tube technology, worth accommodating the heat and the bulk? Thirty years in business convinces us that, for many music lovers, the difference is indeed worth the effort.”